Means for drilling holes in rock formation at or below the earth&#39;s surface



H. L. FOSTER OLE THE Ju`1 April '7,- 1953 INVENTOR. -Houmno L. FpsTER.

FORMATIONS FACE NG H S IN ROCK W EARTHS SUR Filed y 30, 1949 R DRILLI OR BELO ArTcRNEY,

` ing at the other end to the barrel.

Patented Apr. 7, 1953 UNITED STATES PATENT OFFICE 2,634,106 MEANS FOR DRILLING HOLES INKROOK FORMATION AT OR BELOW This invention relates to a means for drilling holes in rock formation at or below the earths surface and it is to be understood as being connected with `apparatus for rotating the drill to form a core, means being provided' to break the core at successive intervals as the drilling proceeds.

These and other objects and features of the invention are hereinafter more iully described and claimed and apparatus embodying my invention is Shown in the accompanying drawing in whichn Fig. 1 is a longitudinal section of the apparatus.

Fig. 2 is a cross section on an enlarged scale of the apparatus taken on line 2*-2 of Fig. l.

Fig. Bis a longitudinal section showing an alternative apparatus. y

Fig. 4 is a fragmentary longitudinal section of another variation.

Heretofore in hard rock formation it has been necessary to cease drilling after a certain length of core has been formed and then to break the formed core to permit removal from the hole, either by pulling or by applying torsional strain through rotation of the drill pipe, each of which operations may result in breakage of equipment and a costly fishing job., The elastic properties of various roel; formations such as limestone, granite, sandstone and the like are available in literature or may be determined from tests.

This invention makes use of those properties known as the modulus of elasticity, the modulus of rupture in bending and the 4shearing strength.

The principal feature of lmy invention resides in the means for exerting a transverse pressure on the rock corewithin the drill whereby bend-V ing stresses are set up at the base vof the core and, when the said Stresses exceed the modulus of rupture, the core is caused to break off automatically as drilling progresses,

The device according to my invention involves a barrel l of cylindrical form having a corev bit Ia at its lower end and the upper end is threaded to a member 2 which is internally threaded as indicated at 3 to receive the threaded end of an operating or rotating element vnot shown inthe drawing. Intermediate the ends of the member 2 is a cylindrical chamber 4 having apertures 5 and 6 at an angle one to the other and Opening to the cylindrical portion at one end and open- The lower portion 'i of the member 2 has a longitudinal recess 8 and a longitudinal recess 9 axially aligned with an Opening to the lower end of the recess THE . v 2 8 and of less diameter than the diameter of the recess 8. In the recess is a ball I0 engaging the inclined seat i I. A pin I2 having a threaded end I3, extends transversely of the longitudinal recess 8 to retain the ball within the recess B and limit the extent of movement or" the ball on reciprocation of the drill. A barrel I4 is in threaded relation at its upper end with the threaded end of the lower portion of themember 2. The barrel I is within the tubular element I and has a downwardly and outwardly inclined eccentrically positioned lug'y I5, the inner face of which has a portion parallel with and spaced from the opposite side ofelement Ill a distance approximately equal to the diameter of the core le being formed in the drilling operation. The longitudinal axis of the lug and inner wall of element Id coincides with the axis of the portion Ilia of the core when the parts are in the position shown in Fig. 2. `Lug I5 has a flat top surface arranged substantially normal to the longitudinal axis of element It, and is adapted to support a severed or broken core, thereon.

As the drilling proceeds the upper end of the vcore engages the inclined face Ia of the. lug I5 which exerts a lateral pressure thereon. The inner diameter of the bit Ia `which forms the core IB is of less diameter than the interior diameter of the barrel I4. The latter has an up wardly and inwardly inclined face IS on one side opposite to and spaced above the` lug I5 for recenterng the core.` Furthermore the distance between face IS and the top of lug I5 is Vat least slightly greater .than the length of the Severed core Ia so that its lower end clears lug I5 before the upper end engages face I8. Thus, as the drilling proceeds, the upper end of the core engages the inclined face Ita of the lug I5 andrbreaks off `the core as indicated at Ib. Upon further drilling the broken off core is onset from the new core Vbeing formed and is pushed upwardly into the barrel If, as indicated at IBa, while compressing the spring, II'I attached to the barrel It. Said spring is preferably a leaf spring of exterior convex formas shown in Fig. 2 and extends longitudinally of the element It, being suitably secured thereto, preferably at its lower end, and arranged so as to be above lug Iii. VWhen the bottom of portion ISa reaches slightly above the top of lug I5 it is pushed laterally by the spring Il so that all portions Ita above the lug I5 are supported by the lug. Any broken-oir portion I6 is retained Within the barrel Iii by the customary core catcher 20, but it is noted that that is the full extent of the load upon the core catcher, so that on withdrawal of element I4 from the drilled hole the severed cores cant drop out.

As the drilling proceeds a number of the prtions Ia are formed and, when the barrel I4 is practically filled with the severed portions I6a, the drill is removed from the hole and the broken portions are easily recovered from the barrel I4.

In the alternative form of the invention shown in Fig. 3 the member 2a corresponds to the member 2 shown in Fig. 1 and has passageways 5a and 6a. corresponding to the passageways 5 and 6 of Fig. 1 but the threaded element 1a, corresponding to the element I of Fig. 1, is separated from the body 2a by ball bearing elements I9.Y

lar element I4 of Fig. 1 and has theV same functions.

In either form of the invention the wall of the `barrel I4 or I4a is supported from deflection by the spaced reaction lugs 2| (Figs. 1 and 2) attached to the barrel I opposite the lug I5 which. is subjected to lateral pressure in breaking the end of the core from the rock formation. As the barrel I4 or lila becomes filled with core sections the drill is removed and the core sections recovered.

It is to be understood that in the form of my invention shown in Fig. 1, the lateral pressure exerted on the formed core by the rotating eccentric lug I5 is in a constantly changing radial direction and causes continuous reversals of stress in the rock core thus utilizing the lower value of the modulus of rupture in bending under conditions of stress reversal. In the form of my invention shown in Fig. 3 the barrel I 4a does 'not rotate due to interposition of the ball bearing I9 and the lateral pressure applied by the lug I5 is in a constant direction, the barrel Illa being utilized as a floating core barrel.

It is also to be understood that Where core contamination by the drilling fluid is of no consequence, the barrel I4 may be omitted as in Fig. 4 and the lug I5 attached to the tubular member I without departing from the spirit and scope of my invention. l It is believed obvious from the drawing and foregoing description that the various features and objects of the invention are attained by the functional character and relationship of parts as hereinbefore described.

Having thus briefly described my invention, its utility and mode of operation, what I claim and desire to secure by Letters Patent of the United States is:

1. A drill for the purpose described comprising a tubular member connected at one end with apparatus for rotation thereof, a core bit at the opposite end, a lug on the inner face of one side of the tubular member, said lug having a top supporting surface and a downwardly and outwardly inclined face engageable by one side of the upper end of the core whereby, as the drilling proceeds, an end of the core is broken from the body and the broken portion is moved upwardly within the tubular member, and resilient means upon the inner surface of said tubular 2,684,106 Aff 4 member positioned above said lug engageable with said broken portion for laterally positioning the same upon said lug.

2. A drill for the purpose described comprising a tubular member connected at one end with apparatus for rotating the same, a core bit at the opposite end, a lug on the inner face of one side of the tubular member, said lug having a. downwardly and outwardly inclined face engageable with one side of the upper end of the core whereby, as the drilling proceeds, the core is broken and the broken portion positioned with its longitudinal axis offset relative to the axis of the core being formed, and resilient means on the inner Wall of said tubular member above said lug engageable with the broken core for realigning the broken portion of the core with the longitudinal axis of the core being formed whereby the severed portions of the core are supported upon said lug.

3. A drill for the purpose described comprising a cylindrical member of tubular form connectible at one end with apparatus for rotating'the same, a ringlike core bit at the opposite end, means joined to and projecting within the cylindrical member for breaking a portion of the core from the body thereof, whereby as the drilling proceeds, the tubular member becomes lled with the severed portions, and resilient means upon the interior of said member positioned above said rst means for laterally projecting said broken portion of the core onto said first means in supported relation.

4. In a core drill, a tubular member for receiving a core, a core bit upon the end of said tubular member, a lug on the inner face of one side of the tubular member, said lug having a top horizontally arranged supporting surface and a downwardly and outwardly inclined face engageable with one side of the upper end of the core as it is moved upwardly within said tubular member whereby, as the drilling proceeds, the core is broken and the broken portion positioned with its longitudinal axis odset relative to the axis of the core being formed, and resilient means on the inner Wall of said tubular member above said lug engageable with the broken core for re-aligning the broken portion of the core with the longitudinal axis of the core being formed, whereby the severed portions of the core are supported on said lug.

HOWARD L. FOSTER.

REFERENCES CITED The following references are of record in the ille of this patent:

UNITED STATES PATENTS Number Name Date 812,093v Conner et al Feb. 10, 1885 1,008,904 Harden et al Nov. 14, 1911 v1,720,700 Stone July 16, 1929 2,034,072 Wright Mar. 17, 1936 2,065,725 Newsom Dec. 29, 1936 2,313,806 Crites Mar. 16, 1943 2,488,003 Greighton Nov. 15, 1949 2,537,605 Sewell Jan. 9, 1951 

